X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;ds=sidebyside;f=drivers%2Facpi%2Fdispatcher%2Fdsutils.c;h=462c5d83e747fe558dd79fc7a224e1c0fb87bd2d;hb=f7f1b0f1e2fbadeab12d24236000e778aa9b1ead;hp=df6b0018677905c2fcf283b389f3cbc617577da5;hpb=e3f6fb6212a7102bdb56ba38fa1e98fe72950475;p=linux-2.6.git diff --git a/drivers/acpi/dispatcher/dsutils.c b/drivers/acpi/dispatcher/dsutils.c index df6b00186..462c5d83e 100644 --- a/drivers/acpi/dispatcher/dsutils.c +++ b/drivers/acpi/dispatcher/dsutils.c @@ -54,8 +54,118 @@ ACPI_MODULE_NAME ("dsutils") +/******************************************************************************* + * + * FUNCTION: acpi_ds_clear_implicit_return + * + * PARAMETERS: walk_state - Current State + * + * RETURN: None. + * + * DESCRIPTION: Clear and remove a reference on an implicit return value. Used + * to delete "stale" return values (if enabled, the return value + * from every operator is saved at least momentarily, in case the + * parent method exits.) + * + ******************************************************************************/ + +void +acpi_ds_clear_implicit_return ( + struct acpi_walk_state *walk_state) +{ + ACPI_FUNCTION_NAME ("ds_clear_implicit_return"); + + + /* + * Slack must be enabled for this feature + */ + if (!acpi_gbl_enable_interpreter_slack) { + return; + } + + if (walk_state->implicit_return_obj) { + /* + * Delete any "stale" implicit return. However, in + * complex statements, the implicit return value can be + * bubbled up several levels. + */ + ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, + "Removing reference on stale implicit return obj %p\n", + walk_state->implicit_return_obj)); + + acpi_ut_remove_reference (walk_state->implicit_return_obj); + walk_state->implicit_return_obj = NULL; + } +} + + #ifndef ACPI_NO_METHOD_EXECUTION +/******************************************************************************* + * + * FUNCTION: acpi_ds_do_implicit_return + * + * PARAMETERS: return_desc - The return value + * walk_state - Current State + * add_reference - True if a reference should be added to the + * return object + * + * RETURN: TRUE if implicit return enabled, FALSE otherwise + * + * DESCRIPTION: Implements the optional "implicit return". We save the result + * of every ASL operator and control method invocation in case the + * parent method exit. Before storing a new return value, we + * delete the previous return value. + * + ******************************************************************************/ + +u8 +acpi_ds_do_implicit_return ( + union acpi_operand_object *return_desc, + struct acpi_walk_state *walk_state, + u8 add_reference) +{ + ACPI_FUNCTION_NAME ("ds_do_implicit_return"); + + + /* + * Slack must be enabled for this feature, and we must + * have a valid return object + */ + if ((!acpi_gbl_enable_interpreter_slack) || + (!return_desc)) { + return (FALSE); + } + + ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, + "Result %p will be implicitly returned; Prev=%p\n", + return_desc, + walk_state->implicit_return_obj)); + + /* + * Delete any "stale" implicit return value first. However, in + * complex statements, the implicit return value can be + * bubbled up several levels, so we don't clear the value if it + * is the same as the return_desc. + */ + if (walk_state->implicit_return_obj) { + if (walk_state->implicit_return_obj == return_desc) { + return (TRUE); + } + acpi_ds_clear_implicit_return (walk_state); + } + + /* Save the implicit return value, add a reference if requested */ + + walk_state->implicit_return_obj = return_desc; + if (add_reference) { + acpi_ut_add_reference (return_desc); + } + + return (TRUE); +} + + /******************************************************************************* * * FUNCTION: acpi_ds_is_result_used @@ -76,7 +186,6 @@ acpi_ds_is_result_used ( { const struct acpi_opcode_info *parent_info; - ACPI_FUNCTION_TRACE_PTR ("ds_is_result_used", op); @@ -88,6 +197,19 @@ acpi_ds_is_result_used ( } /* + * We know that this operator is not a + * Return() operator (would not come here.) The following code is the + * optional support for a so-called "implicit return". Some AML code + * assumes that the last value of the method is "implicitly" returned + * to the caller. Just save the last result as the return value. + * NOTE: this is optional because the ASL language does not actually + * support this behavior. + */ + acpi_ds_do_implicit_return (walk_state->result_obj, walk_state, TRUE); + + /* + * Now determine if the parent will use the result + * * If there is no parent, or the parent is a scope_op, we are executing * at the method level. An executing method typically has no parent, * since each method is parsed separately. A method invoked externally @@ -95,29 +217,10 @@ acpi_ds_is_result_used ( */ if ((!op->common.parent) || (op->common.parent->common.aml_opcode == AML_SCOPE_OP)) { - /* - * If this is the last statement in the method, we know it is not a - * Return() operator (would not come here.) The following code is the - * optional support for a so-called "implicit return". Some AML code - * assumes that the last value of the method is "implicitly" returned - * to the caller. Just save the last result as the return value. - * NOTE: this is optional because the ASL language does not actually - * support this behavior. - */ - if ((acpi_gbl_enable_interpreter_slack) && - (walk_state->parser_state.aml >= walk_state->parser_state.aml_end)) { - ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, - "Result of [%s] will be implicitly returned\n", - acpi_ps_get_opcode_name (op->common.aml_opcode))); - - /* Use the top of the result stack as the implicit return value */ - - walk_state->return_desc = walk_state->results->results.obj_desc[0]; - return_VALUE (TRUE); - } - /* No parent, the return value cannot possibly be used */ + ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "At Method level, result of [%s] not used\n", + acpi_ps_get_opcode_name (op->common.aml_opcode))); return_VALUE (FALSE); } @@ -262,9 +365,8 @@ acpi_ds_delete_result_if_not_used ( } if (!acpi_ds_is_result_used (op, walk_state)) { - /* - * Must pop the result stack (obj_desc should be equal to result_obj) - */ + /* Must pop the result stack (obj_desc should be equal to result_obj) */ + status = acpi_ds_result_pop (&obj_desc, walk_state); if (ACPI_SUCCESS (status)) { acpi_ut_remove_reference (result_obj); @@ -338,9 +440,8 @@ acpi_ds_clear_operands ( ACPI_FUNCTION_TRACE_PTR ("ds_clear_operands", walk_state); - /* - * Remove a reference on each operand on the stack - */ + /* Remove a reference on each operand on the stack */ + for (i = 0; i < walk_state->num_operands; i++) { /* * Remove a reference to all operands, including both @@ -407,11 +508,7 @@ acpi_ds_create_operand ( return_ACPI_STATUS (status); } - /* - * All prefixes have been handled, and the name is - * in name_string - */ - + /* All prefixes have been handled, and the name is in name_string */ /* * Special handling for buffer_field declarations. This is a deferred @@ -586,7 +683,8 @@ acpi_ds_create_operand ( * * FUNCTION: acpi_ds_create_operands * - * PARAMETERS: first_arg - First argument of a parser argument tree + * PARAMETERS: walk_state - Current state + * first_arg - First argument of a parser argument tree * * RETURN: Status *